UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - NCX-5 powered by NCX-A keeps blowing fuse

Station X · 29th Jan 2020, 11:24 am

First check the input voltage to the PSU. The diagram says 117 VAC (Nominal 120VAC), but the voltage delivered from your 240V/120V transformer may be higher than that, particularly if the mains voltage is high in your area.

Voltages quoted will be on load. Check that all valves are lighting up and fully loading the LT supply.

I suspect that the 700 VDC supply is only used on transmit, so must be measured with the transmitter keyed up and operating correctly.

EDIT. Crossed with snowman al.

29th Jan 2020, 11:24 am	#72
Station X Moderator Join Date: Jan 2003 Location: Ipswich, Suffolk, IP4, UK. Posts: 21,289	Re: NCX-5 powered by NCX-A keeps blowing fuse First check the input voltage to the PSU. The diagram says 117 VAC (Nominal 120VAC), but the voltage delivered from your 240V/120V transformer may be higher than that, particularly if the mains voltage is high in your area. Voltages quoted will be on load. Check that all valves are lighting up and fully loading the LT supply. I suspect that the 700 VDC supply is only used on transmit, so must be measured with the transmitter keyed up and operating correctly. EDIT. Crossed with snowman al. __________________ Graham. Forum Moderator Reach for your meter before you reach for your soldering iron.